Automatic regulator for electric circuits.



No. 696,473. Patented Apr. l, [902.

F. C. NEWELL.

AUTOMATIC REGULATOR FOR ELECTRIC CIRCUITS.

(Application filed Apr. 28, 1900.)

(No Model.)

INVINTOR,

Ma M UNITED STATES PATENT OFFICE.

FRANK O. NE\VELL, OF XVILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE"WESTINGHOUSE AIR BRAKE COMPANY, OF IITTSBURG, PENNSYLVANIA, ACORPORATION OF PENNSYLVANIA.

AUTOMATIC REGULATOR FOR ELECTRiC ClRCUITS.

SPECIFICATION forming part of Letters llatent No. 696,473, dated April1, 1902. Application filed April 28, 1900. Serial No. 14,687. (Nomodel.)

To all wltom, it may concern.-

Be it known that I, FRANK O. NEWELL, a citizen of the United States,residing at Vilkinsbnrg, county of Allegheny, State of Pennsylvania,have invented or discovered a certain new and useful Improvement inAutomatic Regulators for Electric Circuits, of which improvement thefollowing is a specification.

My invention relates to automatic regulators for electric circuits; andits object is to provide an improved regulator which is adapted to beinserted. in a gencrator-circuit and arranged to shunt a part of thecurrent around the field of the generator when the strength of thecurrent reaches or exceeds a certain point.

The invention consists in a shunt-circuit with its ends connected toopposite sides of the field of the generator and a solenoid in thegenerator-circuit adapted to open or close the shunt-circuit, accordingto the strength of the current in the generator-circuit.

The invention also consists in certain combinations and arrangement ofparts, as hereinafter described, and set forth in the claims.

In the accompanying drawings, which form a part of this specification,Figure 1 represents a front elevation and partial section of theregulator. Fig. 2 is a View of the interior of the casing of theregulator, showing the coils of the shunt-circuit, the cover of thecasing carrying the solenoids being removed. Fig. 3 is a diagrammaticview showing the regulator applied to an electric braking-circuit forcars.

The regulator is constructed with a casing 4, having a cover 5, on whichare carried the solenoids 6. In this instance I have shown a compoundsolenoid having two movable cores 7 7, connected at their outer ends bya cross piece or head 8, although a single solenoid may be used.

9 represents a projection on the cover of the casing and composed ofnon-conducting material. This projection carries the metalliccontact-surfaces 1O 10, connected to the binding-posts 11 11, to whichare attached the wires of the shunt-circuit S. The head of thesolenoid-cores is connected to the switch 12 by a rod 13, of insulatingmaterial, which slides through an opening in the projection 9. Theswitch 12 is provided with contactpoiuts 171:, made up of a series offlexible and elastic laminations, whereby a yielding and elastic contactis secured when the shunt-circuit is closed and the points l t makecontact with the plates or surfaces 10.

The solenoids 6 are provided at their inner ends with short stationarycores 15 15, connected by the head 16, and the cores are of such lengthsthat a short air-space is provided between the ends of the stationarycores and the ends of the movable cores when the latter are drawn inwardto the full extent of their movement. The main circuit is connected atpoints 17 and 18, so that the current of the main circuit passes throughthe coils. The casing is also provided with bindingposts 20, 21, 22, and23, by means of which the coils R R are connected into theshuntcircuitS.

In Fig. 3 is shown diagrammatically the application of the regulator tothe braking-circuit of a car. A indicates the armature, F the field ofthe generator, and B the magnetic brake device located in the circuit.This circuit from the generator also passes through the coils (3 of thesolenoids.

The ends of the shunt-circuit S are connected to the braking-circuit onopposite sides of the field, and the switch 12 is operated by thesolenoids to make and break the shuntcircuit at the points 10 10.

In the use of the motor as a generator for supplying a braking-circuiton a car it has been found that there is often too much currentgenerated for the proper application of the brake, and variousresistance devices have been devised for restricting the current to thebrake-magnets. My improvement has the advantage that the regulatorinstead of introducing resistance into the circuit shunts a part of thecurrent around the field of the generator, and thus prevents thegeneration of an excessively strong current.

As shown in Fig. 1, the regulator is placed in a vertical position, andthe movable cores 7, with the head 8, normally occupy their lower oroutermost position by gravity. In this position the head 8 rests againstthe projection 9, of insulating material, and the shunt-circuit isbroken. The vertical position of the solenoids is preferred; but thedevice will also operate in other positions, in which case any ordinarymeans, such as a light spring, may be provided to normally keep theswitch open. When the strength of the current passing through the coilsof the solenoids is sufficient to overcome the weight of the switch withthe head and movable cores, the cores are drawn up and the switchassumes its closed position, with contact-points 14 hearing against theplates 10, The shunt-circuit is now closed, and consequently lesscurrent from the armature passes'through the field of the generator.Consequently the strength of the braking-current is reduced until it issomewhat below the point at which the device is set to operate. Then thehead falls and the shunt-circuit is broken. The weight of the movingparts is properly proportioned so that the regulator will operatepositively at a certain strength of current, and by the arrangement ofthe stationary cores and the spaces between the ends of the stationaryand movable cores the switch may be held closed until the strength ofthe current has been reduced a certain number of amperes below that atwhich the regulator is set to act. This may be varied by varying thelength of the spaces between the ends of the stationary and movablecores of the solenoid. It will thus be seen that the regulatorautomatically limits the strength of the current generated and preventsit from becoming so high as to interfere with the proper operation ofthe brake-magnets.

Having now described my invention, what I desire to claim and secure byLetters Patent is-- 1. An automatic regulator for electric circuits,comprising a normally open shunt-circuit, two contact-plates for theshunt-circuit,

a solenoid having a movable core, and a rod operated by said core andcarrying two contact-plates for the shunt-circuit secured to the block,a solenoid, a movable core therefor provided with a rod carrying twocontact- 4:. An automatic regulator for electric circuits, comprising acasing, a normally open shunt-circuit having a resistance-coil in thecasing, a solenoid carried by the casing and having a movable coreprovided with a head,

a block of insulating material secured to the casing, two contact-platesfor the shunt-circuit carried by the insulating-block and a switchconnected to said head and having two contact-points for closing theshunt-circuit when an excessive current passes through the solenoid.

5. An automatic regulator for electric circuits, comprisinga casing, ashunt-circuit having resistance-coils in the casing, a solenoid mountedin a vertical position on the casin g, a stop secured to the casing andadapted to support the movable core of the solenoid when theshunt-circuit is open and av switch in the shunt-circuit operated by thesolenoid.

6. In an electric system, agenerator, a generator-circuit,ashunt-circuit around the field of the generator, said shunt-circuitbeing normally open, a solenoid in the generator-circuit, twocontact-plates in the shunt-circuit, a rod connected to the movable coreof the solenoid and carrying two contact-points position when theshunt-circuit is open and a switch in the shunt-circuit operated by thesolenoid.

In testimony whereof I have hereunto'set my hand.

I FRANK o. NEWELL. Witnesses: d

R. F. EMERY, J AS. 13. MACDONALD.

